NFPA 70E PPE Categories Explained
Arc flash studies assign a PPE category (or a specific calculated incident energy value) to each piece of equipment. Here's what that means in practice.
The Two Approaches
NFPA 70E offers two methods: the incident energy analysis method (a calculated cal/cm² value specific to each piece of equipment — this is what a proper arc flash study produces), and the PPE category method (a simplified table-based approach usable only under specific conditions defined in NFPA 70E Table 130.7(C)(15)(a)). Most facilities with a completed study use the calculated incident energy value directly, since it's more precise than the table method.
General PPE Category Guidance
| Category | Approx. Incident Energy | Typical PPE |
|---|---|---|
| PPE Category 1 | Up to 4 cal/cm² | Arc-rated shirt/pants or coverall, face shield or arc-rated hood, safety glasses, hearing protection, leather gloves |
| PPE Category 2 | 4-8 cal/cm² | Arc-rated shirt/pants, arc-rated flash suit hood, balaclava, safety glasses, hearing protection |
| PPE Category 3 | 8-25 cal/cm² | Arc flash suit (jacket & pants), arc-rated flash suit hood, gloves, leather footwear |
| PPE Category 4 | 25-40 cal/cm² | Higher-rated arc flash suit, hood, gloves, leather footwear |
These are general references, not a substitute for your facility-specific study results. Always use the actual calculated incident energy from your study, not a generic table, when it's available.
Why This Matters for Purchasing PPE
A completed arc flash study is what lets you buy the right PPE — not too little (a safety risk) and not too much (an unnecessary cost and mobility burden on workers). This is one of the most direct financial and safety returns on getting a proper study done.